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Biomedical subjects

M W Yang

Publications and source records attributed to M W Yang.

At least 19 recordsLinked to original sources
PubMed2001

Evaluation of learning effectiveness in endotracheal intubation by the use of a laryngoscope in combination with a flexible fiberoptic bronchoscope.

BACKGROUND: Accidental esophageal intubation may cause lethal complications when undetected. We developed a laryngoscope, which utilizes a laryngoscope blade incorporating with a flexible fiberoptic bronchoscope for teaching new learners. We compared two teaching methods, i.e. the traditional method and the new method we contemplated, for teaching new interns. METHODS: We selected new interns as our study group. Everyone had six turns, four of which for the traditional method (T) and two of which for the new method (N), to perform the procedure under the guidance of a teaching supervisor. The interns were assigned randomly to one of three groups. Group 1 used the series of TTTTNN; group 2, TTNNTT; and group 3, NNTTTT. We used success or failure of intubation as the result of our evaluation. Statistical analyses were performed by chi-square test. RESULTS: 84 interns performed 504 endotracheal intubation trials during a period of 4 years. There was a 91.7% success rate with the new method and a 78.9% success rate with the traditional technique (P < 0.05). The group to which the new method was initially taught achieved the highest success rate of intubation and the greatest feeling of satisfaction according to a self-evaluation record. Of the failed intubations, 82.4% were due to performing the procedure in more than one minute, 15.3% due to esophageal intubation and the remaining 2.3% due to contact bleeding of teeth or oral trauma. CONCLUSIONS: By using the new teaching method, the supervisor could easily teach and assess the success of the new learners. Besides, esophageal intubation could be reduced to a minimum with subsequent increase of success rate.

Anesthesiology↗
PubMed2001

Diagnosis of progressive compression of the aortic true lumen with intraoperative transesophageal echocardiography during repair of dissection of thoracic aorta--a case report.

We report an incident of progressive compression of the true lumen of aorta which happened immediately after cardiopulmonary bypass (CPB) and was diagnosed with intraoperative transesophageal echocardiography (TEE) in a patient undergoing an emergent repair of type A aortic dissection under femoral perfusion. During the CPB period, intraoperative TEE revealed gradual expansion of the false lumen which nearly obstructed the true lumen of the dissected aorta. The possible mechanism was related with distension of the false lumen by a dominant flow from retrograde femoral perfusion of CPB. With the application of intraoperative TEE, we could easily detect the hemodynamic changes of thoracic aorta and find the real causes so as to solve the perfusion abnormalities.

Adult↗
PubMed2001

Anesthetic management of a patient with relapsing polychondritis--a case report.

Relapsing polychondritis is a rare multisystem disorder of uncertain etiology. It is characterized by recurrent and progressive destruction of both elastic and hyaline cartilages as well as connective tissue. Respiratory tract involvement is associated with high mortality and morbidity. General anesthesia may be required in these patients for tracheostomy, bronchoscopy, nasal reconstruction, aortic valve replacement, and recent tracheobronchial stenting which they usually sustain. Tracheostomy was once the most likely surgical procedure in relapsing polychondritis. However, this procedure is only effective in patients with upper subglottic involvement. In cases of extensive tracheobronchial involvement, tracheostomy is ineffective because the distant tracheal collapse below the tracheostomy is still unresolved. We would like to report a case of relapsing polychondritis with tracheobronchial involvement, who underwent an emergent tracheostomy. Tracheostomy with continuous positive airway pressure (CPAP) effectively improved her airway collapse. Herein, we also discuss the anesthetic management after review of the current literature.

Anesthesia↗
PubMed1999

The use of multiplane transesophageal echocardiography to evaluate residual patent ductus arteriosus during video-assisted thoracoscopy in adults.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) has emerged as an innovative and popular procedure for interruption of patent ductus arteriosus (PDA), while intraoperative transesophageal echocardiography (TEE) has proven to be an effective monitor in the evaluation of residual patency. Previous reports on the adequacy of surgical interruption of PDA under VATS and TEE are available for pediatric patients, but only limited information is available for adults with PDA. MATEIALS AND METHODS: Between August 1995 and October 1997, we monitored 35 adult patients undergoing PDA interruption via VATS with Hewlett-Packard color Doppler multiplane TEE throughout the procedure. The average PDA diameter was 10.2 +/- 1.8 mm. All the PDA were completely ligated. RESULTS: Thirty-two patients showed no ductal flow after double ligation. In the other three patients, residual flow was detected intraoperatively after double ligation, but it was quickly abolished by the third ligation. One patient showed faint ductal flow by transthoracic echocardiography at postoperative follow-up, but no reintervention was needed. CONCLUSIONS: Our study showed that, with the refinement of adult PDA interruption via VATS, intraoperative multiplane TEE provides higher resolution for direct evaluation of the entire course of PDA ligation without interrupting the surgical procedure and minimizes the incidence of complications.

Adult↗
PubMed1998

Surgical closure of atrial septal defect. Minimally invasive cardiac surgery or median sternotomy?

BACKGROUND: Closure of ostium secundum atrial septal defect (ASD) vis median sternotomy (MS) is a simple procedure for most cardiac surgeons. Minimally invasive cardiac surgery (MICS) has recently been applied in the management of intracardiac lesions. METHODS: We report our experience in surgical closure of isolated ASD via MICS in 60 patients and via MS in 58 patients. There was no difference between these two groups in gender, age, body weight, ratio of systemic to pulmonary blood flow, and pulmonary arterial pressure. RESULTS: The duration of cardiopulmonary bypass was significantly longer in the MICS group than in the MS group [27 to 126 min (42 +/- 12) and 14 to 158 min (27 +/- 11), respectively; (p < 0.001]. However, the length of incision, incidence of temporary pacemaker wire insertion rate, duration of endotracheal intubation, timing of oral intake, postoperative day drainage amount, incidence of parenteral analgesic injection, postoperative length of stay, and return to normal activity interval were significant shorter and lower in patients of the MICS group than in those of the MS group. All the patients recovered rapidly from the surgery. Follow-up was complete in all patients, with no late complications and no residual shunt. CONCLUSION: Our results suggest that MICS is a good option for surgical closure of ASD.

Adolescent↗
PubMed1998

Minimally invasive cardiac surgical techniques in the closure of ventricular septal defect: an alternative approach.

BACKGROUND: Minimally invasive cardiac surgical techniques recently have been applied in the management of a variety of intracardiac lesions. METHODS: Fourteen patients (6 boys and 8 girls; age, 8.9 +/- 5.5 years; body weight, 29.0 +/- 13.5 kg) were operated on using minimally invasive cardiac surgical techniques for the closure of a ventricular septal defect (subarterial in 11 patients and perimembranous in 3 patients). The operations were performed through a left anterior minithoracotomy and were guided by video-assisted endoscopic techniques under femorofemoral cardiopulmonary bypass. The myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest. The right ventricular outflow tract was entered after pericardiotomy was performed. RESULTS: Closure of the defect (directly in 4 patients and by patch in 10 patients) was performed successfully in all patients. A right ventricular outflow tract obstruction and ruptured sinus of Valsalva aneurysm also were repaired in 1 patient each. The duration of cardiopulmonary bypass was 41 +/- 10 minutes (range, 28 to 100 minutes) and the total operative time was 2.2 +/- 0.8 hours (range, 1.3 to 3.5 hours). All the patients recovered rapidly from their operation and had an uneventful postoperative course. Follow-up (mean, 6.2 months; range, 6 to 9 months) was complete in all patients. There were no late deaths. Transthoracic echocardiographic examination showed no residual shunt and no aortic regurgitation in all patients. CONCLUSIONS: Our experience demonstrates that minimally invasive cardiac surgical techniques are technically feasible and an alternative option for the repair of a ventricular septal defect.

Cardiac Surgical Procedures↗
PubMed1998

Video-assisted minimal access in excision of left atrial myxoma.

BACKGROUND: Minimal access surgery with video-assisted endoscopy has been applied to the correction of intracardiac lesions. We report our experience using this technique in surgical excision of left atrial myxoma in 3 patients. METHODS: From November 1995 to March 1997, 3 female patients, ages 45 to 80 years (mean, 62.7 years), received emergency operations for excision of left atrial myxoma. These operations were performed through a right anterior submammary minithoracotomy or right parasternal incision with the assistance of endoscopy during femoro-femoral cardiopulmonary bypass. The myocardium was protected by continuous coronary perfusion with fibrillatory arrest or cardioplegic arrest with aortic cross-clamping. RESULTS: All the tumors were excised completely through the right atrial approach. The bypass time was 92 to 148 minutes (mean, 111 minutes). The operation time was 3.2 to 4.4 hours (mean, 3.7 hours). There were no hospital deaths. Follow-up, which ranged from 6 to 19 months (mean, 10.5 months), was complete in all patients. Transthoracic echocardiographic examination showed good ventricular function without any residual tumors. Patients were found to be in New York Heart Association functional class I or II. They were satisfied with the good cosmetic healing of the incision. CONCLUSIONS: Our experience demonstrates that minimal access surgery is a technically feasible, safe, and effective procedure in surgical excision of left atrial myxoma.

Aged↗
PubMed1998

Totally minimally invasive cardiac surgery for coronary artery disease.

OBJECTIVE: We report our experience using minimally invasive techniques both to perform coronary artery bypass and harvesting of saphenous vein grafts in 25 patients with left main or triple vessels disease. METHODS: From March 1997 to June 1997, 25 patients received elective coronary artery bypass grafting using minimally invasive surgical techniques for left main or triple vessels disease. Saphenous vein grafts were harvested using minimally invasive techniques under direct vision. The coronary artery bypass grafting was performed through a limited left anterior parasternal minithoracotomy under femoro-femoral or aorto-atrial cardiopulmonary bypass. The myocardium was protected by antegrade infusion of cold blood cardioplegic solution while the aorta was cross-clamped. RESULTS: Three to four distal anastomoses were performed with the saphenous vein graft and the left internal thoracic arterial graft. The aortic cross-clamp time was 60-135 min. The duration of cardiopulmonary bypass was 89-172 min. The postoperative course was uneventful for all patients. All patients were found to be in New York Heart Association functional class I or II on follow-up from 3-7 months after surgery. CONCLUSIONS: Minimally invasive coronary artery surgery is technically feasible and can be performed in left main or triple vessel disease safely and effectively for complete revascularization.

Cardiopulmonary Bypass↗
PubMed1998

Minimally invasive cardiac surgery for intracardiac congenital lesions.

OBJECTIVE: Minimally invasive cardiac surgery has recently been applied to the correction of intracardiac lesions. This report reviews our experience of minimally invasive cardiac surgery in 119 patients with intracardiac congenital lesions. METHODS: From October 1995 to April 1997, 119 patients (48 male and 71 female, aged 0.9-65 years old, 18.5+/-17.8) received elective minimally invasive cardiac surgery at Chang Gung Memorial Hospital, Taipei, Taiwan for repair of atrial septal defect (96 patients) or ventricular septal defect (23 patients). The operations were performed through right submammary incision (ASD) or left parasternal minithoracotomy (VSD), under femoro-femoral or femoro-atrial cardiopulmonary bypass with fibrillatory arrest. RESULTS: All of the defects were repaired successfully. The bypass time was 25-125 min (46+/-18). The operation time was 1.5-5.2 h (2.8+/-0.8). The postoperative course was uneventful in all patients. Follow-up (1.0-18.2 months, mean 7.3) was complete, with no late deaths or residual shunt. All patients were found to be in NYHA functional class I or II. CONCLUSION: Our experience demonstrate that minimally invasive cardiac surgery is a technically feasible, safe, and effective procedure in surgical correction of selective simple intracardiac congenital lesions, yielding good short-term results.

Adolescent↗
PubMed1998

Video-assisted cardiac surgery for intracardiac tumors.

OBJECTIVE: To present our experience in surgical excision of intracardiac tumors in three patients using video-assisted cardiac surgical techniques. METHODS: Three patients received emergency video-assisted cardiac surgery for excision of right atrial or left atrial tumors. These surgeries were performed through right anterior submammary minithoracotomies and guided by video-assisted endoscopic techniques by projected images on a video monitor while under femoro-femoral cardiopulmonary bypass. The myocardium was protected by continuous coronary perfusion with fibrillatory arrest. Conventional instruments were used. RESULTS: All but one of the tumors were excised completely. The bypass time was 88-148 min. The operation time was 3.5-4.4 h. There were no operative deaths. Pathological examination of the tumors showed left atrial myxoma, metastatic left atrial choriocarcinoma, and right atrial lymphoma. One patient died from non-cardiac origin 5 weeks after discharge. Follow-up was completed with the two survivors. Transthoracic echocardiographic examination showed good ventricular function without any residual tumors. They were both in New York Heart Association functional class I or II. They were satisfied with the cosmetic healing of their incisions. CONCLUSION: Video-assisted cardiac surgery is technically feasible and can be performed in surgical excision of intracardiac tumors.

Adult↗
PubMed1998

Power spectral analysis of arterial blood pressure after spinal anesthesia.

BACKGROUND: The continuous, on-line and real-time analysis of the power spectrum (CORAPS) of systemic arterial pressure (SAP) and heart rate (HR) signals is one of the current progresses in the development of non-invasive indexes for autonomic nervous system. It might be a useful clinical tool to monitor the progress of preganglionic block of sympathetic nervous system and the homeostatsis of cardiac neuroregulation after spinal anesthesia. The purpose of this study is to examine the relationship between the hypotensive response and the changes of components in CORAPS throughout the course of spinal anesthesia. METHODS: In 10 ASA class I-II patients (aged from 17 to 75 years) scheduled for elective surgery, we analyzed the changes of spectrum of systemic arterial blood pressure signals during spinal anesthesia. Spinal anesthesia was performed with 0.5% bupivacaine (dosage at 13-15 mg). For CORAPS, SAP signals were simultaneously relayed to an analog-digital converter connected to a computer. Power spectral density of the data was computed using a fast Fourier transform. The areas of the spectral peaks within each measurement were calculated as the follows: very low (BVLF, 0.01-0.08 Hz), low (BLF, 0.09-0.15 Hz), and high (BHF, 0.16-0.25 Hz). RESULTS: During the time interval (S2 period) when spinal anesthesia was initiated and 15 min thereafter the power density of low frequency (BLF), (1.2 vs. 2.3), and very low frequency (BVLF) components decreased, (3.4 vs. 7.8), in comparison with that at the baseline level (S1 period). We also found the shift of dominance between low frequency (BLF) and high frequency (BHF) in S2 period. The effects of intrathoracic pressure on the venous return may contribute to the increase of power density of BHF components (1.7 vs. 1.1). We also found that even in patients with stable hemodynamic variability, the decrease of BLF and BVLF components, and the shift of dominance were the same as in patients with unstable hemodynamic variability. CONCLUSIONS: It might prove that the cephalic spread of spinal block abolished the sympathetic tone of the autonomic nervous system. These results validated previous speculations of a sympathetic block during spinal anesthesia. More importantly, patients with stable hemodynamic variability still have profoundly sympathetic block with decreased power density of BLF and BVLF. The CORAPS is a good clinical monitoring tool to evaluate the homeostatsis of cardiac neuroregulation after spinal anesthesia.

Adolescent↗
PubMed1998

Airway compression by a biplane pediatric transesophageal echocardiography probe: case report.

Transesophageal echocardiography (TEE) has been extensively used in cardiac surgery to assess cardiac function and anatomical relationships in both adults and children. Newer monitoring devices, despite being labeled "noninvasive", often present significant risks. Physicians should be cautious with the use of TEE in infants and small children, recognizing that oversized probes may inadvertently compress vital structures, resulting in airway or vascular compromise. If severe compression of the airway or vascular structures occurs, TEE monitoring may need to be discontinued. Although technological progress has yielded smaller ultrasonic probes, the TEE probe is significantly larger than most other devices placed in the esophagus. We present in this report a case of airway compression using a small-sized biplane pediatric TEE probe in a child undergoing Blalock-Taussig shunt surgery. Pediatric patients may be more at risk for airway obstruction because of the over-size of the probe-distended esophagus in relation to adjacent airway structures.

Airway Obstruction↗
PubMed1997

Minimally invasive approach for coronary artery bypass surgery.

Forty-two patients, 33 male and 9 female, aged 35.7 to 81.6 years old (mean 62.7), were operated on for left main and/or triple vessel coronary artery disease by using minimally invasive cardiac surgical techniques. A myocardial infarction had occurred in 26 patients (61.9%). The left ventricular ejection fraction ranged from 17 to 83% (52+/-22). The surgeries were performed through left parasternal minithoracotomy (8 to 12 cm in length) under femoro-femoral or aorto-atrial cardiopulmonary bypass. The myocardium was protected by blood cardioplegic solution with the aorta crossclamped. Under direct vision, average 3.8 distal anastomoses were performed in each patient, with the saphenous vein grafts and the left internal thoracic arterial graft. The aortic crossclamp time was 62 to 137 min (80+/-15). The duration of cardiopulmonary bypass was 88 to 168 min (115+/-24). The postoperative course was uneventful in all patients. Follow-up (1.0 to 5.6 months, mean 2.9) was complete in all patients and there were no late deaths or angina. Coronary angiography of ten patients showed patent grafts. Our experience demonstrates that minimally invasive cardiac surgery during cardioplegic arrest is technically feasible and can be performed in coronary artery disease safely and effectively for complete revascularization.

Adult↗
PubMed1997

Video-assisted coronary artery bypass grafting during hypothermic fibrillatory arrest.

BACKGROUND: Hypothermic fibrillatory arrest without aortic cross-clamping is a technique for quieting the heart during coronary artery bypass grafting. This report reviews the preliminary results with this technique in 4 patients having video-assisted coronary artery bypass grafting. METHODS: Four male patients 28.5 to 64.5 years old (mean age, 45.4 years) underwent operation for unstable angina. With video-assisted techniques, coronary artery bypass grafting was performed through a left anterior minithoracotomy with femoral-femoral cardiopulmonary bypass without cross-clamping the aorta. The myocardium was protected by continuous coronary perfusion during hypothermic fibrillatory arrest. RESULTS: A left internal thoracic artery graft was anastomosed to the left anterior descending coronary artery in each patient. The posterior descending branch of the right coronary artery was grafted with a pedicled right gastroepiploic artery in 1 patient. The duration of cardiopulmonary bypass was 72 to 127 minutes (mean duration, 92 +/- 21 minutes). The postoperative course of each patient was uneventful. Follow-up (range, 3.9 to 5.8 months; mean follow-up, 4.9 months) was complete for all patients. There were no late deaths. Coronary angiography showed patent grafts. All patients were in New York Heart Association functional class I or II (mean class, 1.25). CONCLUSIONS: Hypothermic fibrillatory arrest is a simple and effective method of quieting the heart, thereby providing a motionless operative field for video-assisted coronary artery bypass grafting.

Adult↗
PubMed1996

Video-assisted mitral valve operations.

BACKGROUND: Video-assisted endoscopy has been applied frequently in the management of a variety of surgical diseases. However, it has rarely been applied in mitral valve surgery. METHODS: We report 2 patients who received emergency operations for thrombosis of a mitral prosthesis (patient 1, a 68-year-old man) and acute mitral regurgitation due to rupture of anterior chordae (patient 2, a 75-year-old woman). They both had severe congestive heart failure. Cardiogenic shock was noted in patient 2. The mitral valve was approached through a right anterior minithoracotomy with the aid of an endoscope by means of projected images on the video monitor under femorofemoral cardiopulmonary bypass. The aorta was not cross-clamped, and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest. The left atrium was entered posterior to the interatrial groove. Thrombectomy and mitral valve repair were performed successfully. RESULTS: The duration of extracorporeal circulation was 204 and 147 minutes, respectively. Both patients recovered from the operation rapidly with uneventful postoperative courses. CONCLUSIONS: Our preliminary results suggest that video-assisted endoscopic cardiac surgery is technically feasible and could be performed in the milieu of open heart surgery.

Aged↗
PubMed1996

Video-assisted cardiac surgery in closure of atrial septal defect.

BACKGROUND: Video-assisted endoscopy has been applied in the management of a variety of intrathoracic vascular lesions. Here we report its use in the correction of intracardiac congenital defects. METHODS: Eight patients (3 male and 5 female) underwent operation for closure of an atrial septal defect. The patients ranged in age from 2.0 to 60.9 years (mean, 19.2 +/- 19.0 years). The patients weighed 11 to 66 kg (mean, 41.3 +/- 23.5 kg). The ratio of pulmonary blood flow to systemic blood flow ranged from 2.0 to 6.0 (mean, 3.4 +/- 1.3). The mean pulmonary artery pressure was 19.7 +/- 4.0 mm Hg (range, 13 to 24 mm Hg). The operations were performed through a right anterior minithoracotomy and guided by video-assisted endoscopic techniques under femorofemoral or femoral-right atrial extracorporeal circulation. The aorta was not cross-clamped, and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest (rectal temperature, 22.0 degrees +/- 2.0 degrees C). Transesophageal echocardiographic monitoring was maintained during the operations. The right atrium was entered after pericardiotomy. Primary closure of the defect was performed successfully in all patients. Conventional nondisposable instruments were used for dissection, grasping, suturing, and hemostasis. RESULTS: The durations of extracorporeal circulation and operation ranged from 47 to 126 minutes (mean, 80 +/- 31 minutes) and from 2.2 to 4.5 hours (mean, 3.1 +/- 0.8), respectively. All patients recovered from the operation rapidly with an uneventful postoperative course. CONCLUSIONS: Our experience demonstrates that video-assisted cardiac surgery is technically feasible and can be used with excellent results for the repair of congenital heart defects in general.

Adolescent↗
PubMed1996

Double-lumen endotracheal tube intubation in difficult intubation-use the WuScope System: a case report.

Although not an absolute requirement in most cases, there are many anesthetic and surgical advantages for using a double-lumen tube during intrathoracic operations. It is almost impossible that double-lumen tube intubation by conventional methods in patients whose glottis can not be visualized by direct laryngoscopy. We describe the previously unreported method by using The WuScope System for double-lumen endotracheal tube intubation in a patient with acromegaly and difficult airway.

Female↗